This is a request for a 2-photon intravital laser scanning confocal fluorescence microscopy system -"intravital confocal microscope"- for a variety of projects involving confocal imaging of living mice. The system will be installed in the Light Microscopy Core Facility (LMCF), a University core facility that currently serves the optical microscopy needs of several hundred users from across the entire Duke University campus. At present users are substantially limited by the current imaging resources for in vivo imaging. The only upright confocal microscope available for intravital imaging is no longer supported by Zeiss and will need to be decommissioned in the next year or so, and the only 2-Photon confocal microscope available on campus is inverted, obsolete, slow, and is consequently very poorly suited to in vivo imaging. As evidence of Duke University's commitment to the acquisition of state-of- the-art in vivo imaging modalities, the University has committed funds up to $300,000 that would supplement the funds requested herein to enable the integration of 2-photon capability to the system.